Patents Assigned to D & B Supply, Inc.
  • Patent number: 5926111
    Abstract: A system for summoning a service industry worker using pulsed width modulation for remote signalling having a number of signalling switches, each connected to a transmitter. When a switch is activated, the corresponding transmitter transmits an RF carrier modulated by a lower frequency tone, turning the tone on and off in a pattern determined by a unique code assigned to the switch. A central receiver filters the signal from the transmitter and converts the tone pattern to a binary output to a computer. The computer instructs a display unit to turn on a light corresponding to the switch by sending its number in a serial bit stream of all lights that should be on. The bit stream is interpreted by circuits in the display unit using a clock signal. Upon the clock signal, the bit is sent to the appropriate register, which is used to turn on the correct light.
    Type: Grant
    Filed: October 16, 1995
    Date of Patent: July 20, 1999
    Assignee: D & B Supply, Inc.
    Inventors: Charles F. Davis, Joseph V. Bednar